Many patients require closed wound drainage after surgery. Closed wound drainage relies on a drainage tube sewn into a wound. The drainage tube extends out of the wound and connects to a source of vacuum, such as a vacuum container with vacuum level control valve. Fluids gathering in the wound after surgery are moved through the drainage tube and collected in the container. A surgical trocar is a stainless steel implement used to introduce the drainage tube into the wound. The surgical trocar typically is a smooth stainless steel shaft with a point at a leading end to pierce skin, and a ridged connector at a trailing end for attachment to the drainage tube. In use, a rear or trailing end of the surgical trocar is attached to a leading end of the drainage tubing. A surgeon then manually uses the surgical trocar to pierce a hole through the skin (and any fat and muscle) of the patient from the internal surface to the outer (epidermal) skin surface. The surgical trocar is then removed from the drainage tubing, often by cutting through the drainage tubing adjacent the surgical trocar.
Because of the natural presence of blood and during surgery, particularly on the gloved hands of the surgeon, the smooth stainless steel shaft of the surgical trocar often becomes slippery and difficult to grip. The slippery surgical trocar rotates in or slips through the surgeon's grip when trying to pierce through the patient's skin and when trying to pull the trocar through from the external side of the skin after initial piercing. This slippage risks injury to the surgeon and delay to the surgical procedure and possible damage to the patient. Attempts have been made to resolve this slippage problem.
Published U.S. Pat. No. 4,490,136 proposes a flattened oblong section straight or angled shaft surgical trocar, the flattened oblong shape aims to reduce the risk of slipping in the surgeon's hands, and the oblong hole produced by the angled sharpened leading end aims to produce a fissure shaped incision. The drainage tube is connected to a barbed spigot at the rear end of the trocar protected by an enlargement that narrows at its leading end and flares out to an enlarged end where the drainage tube connects to the trocar. However, the shaft of this trocar is smooth and does not provide any grip feature on its surface to reduce the likelihood of slipping. Also, the barbed spigot causes the leading end of the drainage tube to flare out to get over the widest part of the barb. Hence, U.S. Pat. No. 4,490,136 proposes the enlarged, portion to compensate for this forced widening and attempts to smoothly and progressively increase the effective width of the trocar, thereby attempting to avoid a step in width, by providing the gradually widening enlargement portion.
Another attempt to reduce the slippage problem has been to provide a series of shallow grip notches across a portion of the width of the straight shaft of the trocar. However, such notches only have limited grip benefit to prevent the trocar from rotating in the surgeon's hand when piercing the skin, and limited grip benefit when trying to push the trocar through the skin.
One known attempt to improve grip on a trocar to introduce a catheter or other tube into a subcutaneous tunnel is disclosed in GB 2103936A. That document discloses a rod or tube having a hand grip at a proximal end and, at a distal end, a detachable tip for passing smoothly through subcutaneous tissue to introduce the catheter or other tube through the tissue wall. Thus, effectively this document discloses a trocar with detachable handle at the end opposite to the detachable working tip or point of the tool. The hand grip is relatively bulky and does not allow for pre-connection of the catheter prior to making an incision into a patient with the tool. This therefore complicates the catheter introduction procedure and requires a separate step of removing the hand grip and attaching the catheter to the proximal end of the rod or tube.
An alternative attempt of providing improved user grip on a trocar is disclosed in U.S. Pat. No. 4,883,474A. That document provides a tube having a stiffened and sharpened end. The stiffened end is a rigid rod extending inside the tube and the rod is shapeable into a grippable shape to assist the user in maneuvering the rod and tube into and through the desired path in the surgical site. Thus, U.S. Pat. No. 4,883,474 teaches the shaping of a rigid rod within tubing to assist in providing grip.
With the above problems in mind, it has been found desirable to provide an improved surgical trocar that improves grip when pushing the trocar through the skin and reduces the likelihood of the trocar rotating in the surgeon's hand at that time.
Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of admission that the prior art forms part of the common general knowledge in Australia.